From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Delivered-To: caml-list@yquem.inria.fr Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by yquem.inria.fr (Postfix) with ESMTP id B1684BC48 for ; Thu, 31 Mar 2005 20:37:25 +0200 (CEST) Received: from pauillac.inria.fr (pauillac.inria.fr [128.93.11.35]) by concorde.inria.fr (8.13.0/8.13.0) with ESMTP id j2VIbPfR025849 for ; Thu, 31 Mar 2005 20:37:25 +0200 Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id UAA10874 for ; Thu, 31 Mar 2005 20:37:24 +0200 (MET DST) Received: from saul.cis.upenn.edu (SAUL.CIS.upenn.edu [158.130.12.4]) by nez-perce.inria.fr (8.13.0/8.13.0) with ESMTP id j2VIbMLw022330 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO) for ; Thu, 31 Mar 2005 20:37:24 +0200 Received: from localhost (SAUL.CIS.upenn.edu [158.130.12.4]) by saul.cis.upenn.edu (8.12.10/8.12.9) with ESMTP id j2VIb8CP001765; Thu, 31 Mar 2005 13:37:19 -0500 (EST) Date: Thu, 31 Mar 2005 13:37:08 -0500 (EST) Message-Id: <20050331.133708.36930703.eijiro_sumii@anet.ne.jp> To: Francis.Dupont@enst-bretagne.fr Cc: caml-list@inria.fr, sumii@saul.cis.upenn.edu Subject: [OT] Re: webmaster@caml.inria.fr is not a "legal" mail address From: Eijiro Sumii In-Reply-To: <200503311335.j2VDZ0v6069029@givry.rennes.enst-bretagne.fr> References: <20050331.080520.68550579.eijiro_sumii@anet.ne.jp> <200503311335.j2VDZ0v6069029@givry.rennes.enst-bretagne.fr> X-Mailer: Mew version 3.2 on Emacs 20.7 / Mule 4.1 (AOI) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Miltered: at concorde with ID 424C4365.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Miltered: at nez-perce with ID 424C4362.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Spam: no; 0.00; eijiro:01 sumii:01 eijiro:01 sumii:01 bug:01 imho:01 ...:98 ...:98 821:98 wrote:01 wrote:01 rewrite:01 dmitry:01 rfc:02 rfc:02 X-Spam-Checker-Version: SpamAssassin 3.0.2 (2004-11-16) on yquem.inria.fr X-Spam-Status: No, score=0.0 required=5.0 tests=none autolearn=disabled version=3.0.2 X-Spam-Level: Sorry for the off-topic discussion - I didn't expect it to take so long...! > But RFC 1123 says as below, for example...? > > => you mix up the MTA (which canonizes when it can *) and the MUA > (which should accept any valid name). I've always been talking about MTA and never said anything about MUA in this thread. Maybe my wording "illegal mail address" caught your eyes - I should perhaps have said "causing confusion to a major MTA" or something. I also quoted the word "legal" in the first place, meaning that at least some MTAs (such as many configurations of sendmail, i.e., those with "O DontExpandCnames=False" which is the *default* in many versions) indeed rewrite CNAME addresses, not only in envelopes but also in contents, which is well-known to cause confusion. > => you still mix up MTAs and MUAs. In fact, you suggest *your* MTA is > wrong (:-)! Well, as I wrote above, I've never talked about any MUA - I wrote "my server at Penn" in my first message on this topic. I agree that one can argue that some versions/configurations of sendmail are wrong, but they are very common at least. > (I wonder what Dmitry meant by > "webmaster@caml.inria.fr is not routable"...) > > => me too. Hey, you are _so_ picky about his words in your reply...!:-) | => no E-mail address is routable... What do you mean ? The host | caml.inria.fr is routable, i.e., the host which has the (alias) name | caml.inria.fr has a routable IP address (128.93.11.23). > => but they are not more illegal. BTW the Sender-SMTP is likely a MTA. > Today the canonization is considered only as useful (if it is not performed, > the next MTA will have to resolve the alias again) but no more as mandatory > or necessary. I can agree that they are no longer stated as illegal in RFC 2821, but they were in RFC 821 (and 1123) - and there are still many systems which conform to the latter. > => I argue that your MUA should accept what you give as soon as it is > valid and it knows what to do with it. I agree, but again I've never talked about any MUA. > The bottom line is that it is still a bad practice to use aliases in > mail address domains for these reasons. > > => not only it is not a bad practice (the first agent on the path can > resolve the alias, before RFC 2821 it was the first agent using SMTP at > its sending side) but it is a very common practice. What do you believe > aliases are for? I've never said (or even thought) that aliases are bad by themselves - I'm just saying that aliases *in the "domain" part of mail addresses* often cause confusion for the reasons above. You can find many tips on this issue if you google "sendmail CNAME" or something. We might call it a bug of some versions/configurations of sendmail, but they happen to be still common, unfortunately. > => I don't understand this comment about A RRs (do you suggest to use > only litterals?) > => IMHO MX RRs are a nice idea. With HTTP 1.1 virtual hosting they are > more than necessary! Oh, MX is just fine for me, too!:-) Again, I'm just saying that CNAME domains used in mail addresses are known to be problematic at least in practice, and I don't think that such uses are so common as you said - I've only experienced this problem a few times in my billions of e-mail exchanges for >10 years, even though there are many MTAs with this problem. Perhaps my wording "legal/illegal" wasn't correct with respect to the latest RFC, though. Best regards, Eijiro